Treason is a heavy accusation, yet it seems fitting when examining the actions taken by Andrew Mountbatten-Windsor.

Recently unveiled documents from the US Department of Justice reveal that the former prince, now fallen from grace, shared critical financial insights with his friend Jeffrey Epstein. These disclosures had the potential to severely jeopardize the British government’s urgent £45 billion intervention to save the Royal Bank of Scotland during a historic financial crisis.

Andrew is reported to have shared sensitive Aston Martin financial details with an American banker who was not entitled to such information.

Additionally, a high-ranking Palace official allegedly leaked a confidential diplomatic cable concerning UK-China trade relations to one of Andrew’s trusted business partners.

For Andrew, maintaining his relationship with Epstein and benefiting from his financial networks seemed to outweigh any consideration for Britain’s national interest.

While it’s evident that Epstein and other international financiers were eager for such privileged information, the question remains: what did Andrew gain from these exchanges?

He certainly has form when it comes to insider information. In 2008, Andrew demanded that the Serious Fraud Office brief him privately about its investigation into the sale of arms by BAE Systems to Saudi Arabia. Why?

On another occasion, he asked the Treasury for details about a live banking crisis in Iceland – and promptly passed them on to his banker friend David Rowland.

Andrew pictured with The Crown Prince of Bahrain at Ascot in 2010. His links with the Middle East are under increased scrutiny

It seems that the British national interest counted for little when weighed against Andrew’s wish to stay cosy with his close friend Jeffrey Epstein and his lucrative connections in the world of finance, writes Norman Baker

No doubt there are more of these revelations to come. Which is why it’s time for the authorities to stop pussyfooting around and wake up to the seriousness of Andrew’s actions and the damage he has done.

It’s not good enough to hide him away behind a high wall on the Sandringham estate. He must be held to account.

We need a full, open and transparent investigation into Andrew’s time as trade envoy –and his shady business dealings.

We need the publication of all papers relating to his activities held by the Government and by the Palace. He must give evidence to, and answer questions before, a select committee of the House of Commons.

There was a time a few years back when the then prince’s misbehaviour was dismissed as largely harmless, even if eyebrows were raised about the taxpayer bill for his private jets and the best hotels when acting as Britain’s trade envoy. Certainly, there was little official appetite for scrutiny of his activities.

One by one, however, the layers of his deceit have been stripped away like onion rings, each one revealing something more repugnant beneath.

We learnt, for example, that his flights were frequently to destinations which happened to be near a leading golf course.

We learnt that his clodhopping, saloon-bar style of diplomacy abroad could be offensive to Britain’s allies and that he was known by our diplomats abroad as His Buffoon Highness.

We need a full, open and transparent investigation into Andrew’s time as trade envoy – and his shady business dealings, writes Norman Baker (Andrew pictured with Chinese President Xi Jinping)

We learnt that Andrew made a disproportionate number of visits to despotic regimes, particularly those generous to members of the British Royal Family. Did he really need to visit the United Arab Emirates nine times, Qatar five times, and Kuwait, Bahrain and Egypt four times each in just six-and-a-half years?

With time, it became all too obvious that Andrew was using his trade position not to promote Britain’s interests, but his own.

As I explain in my new book, Royal Mint, National Debt, his circle of contacts included individuals convicted of child sexual exploitation, corruption, fraud, serious financial impropriety and gun-running. He has spent time with men accused of torture and even spying against the UK.

The closer to the centre of Andrew we get, the more putrid the stench. And now comes compelling evidence that he has been selling out his own country.

Some people shrug their shoulders and half-excuse all this. Andrew is Andrew, they claim. I say wake up and smell the coffee. Just because this whole sorry saga has been painfully slow – that we have had to spend more than two decades digging for the truth – does not make his actions any less shocking.

We simply cannot let this sort of reprehensible behaviour –whether it is by a member of the Royal Family, a former minister such as Peter Mandelson, or indeed anyone else – pass without a firm response. We cannot let malfeasance by those in authority seem in any way par for the course.

Andrew has led a charmed life and in his arrogant way assumed that the rules that apply to little people did not apply to him.

He relied on the deference shown by Parliament, by the media, by the police who have regularly turned a blind eye, and by the public at large. He was protected, among other things, by the virtual exemption that the Royal Family has secured from the Freedom of Information Act.

All this has to change. Andrew must held to account for what he has done, and now. It is not just the monarchy but democracy that’s at stake.

Norman Baker’s latest book Royal Mint, National Debt is published by Biteback.